Technical Field
The present invention relates to a sheet folding apparatus for folding a sheet with an image formed thereon in half, one-third or the like, for example, and more particularly, to improvements in the folding mechanism.
Description of the Related Art
Generally, this type of sheet folding apparatus has been known as an apparatus for folding a sheet with an image formed thereon by a printing press, printer apparatus or the like to perform finish processing, or to perform finish preprocessing. For example, Japanese Patent Application Publication No. 2009-18494 proposes a system in which a sheet folding apparatus is arranged between an image formation apparatus and a bookbinding apparatus, and sheets with images formed are folded by the sheet folding apparatus and undergo a bookbinding finish. Further, Japanese Patent Application Publication No. 2005-266245 discloses a system in which a sheet folding apparatus is arranged between an image formation apparatus and a post-processing apparatus, folds a sheet with an image formed, and feeds the sheet to the post-processing apparatus.
Meanwhile, as a sheet folding mechanism, such a folding mechanism has been used widely that two pairs of rollers fold a sheet in two or three pairs of rollers fold a sheet in three. For example, Japanese Patent Application Publication No. 2006-76777 discloses a folding apparatus for folding a sheet using three pairs of rollers.
The sheet folding apparatus, which folds a sheet fed from the image formation apparatus, etc. in two or three to transfer to the subsequent apparatus as described above, has been known widely as an image formation system, etc. In this case, conventionally, as proposed in Japanese Unexamined Patent Publication No. 2009-18494 and Japanese Unexamined Patent Publication No. 2005-266245, a path for feeding a sheet that does not undergo folding processing from a carry-in entrance to a carrying-out exit is disposed in the horizontal direction, for example, and a sheet folding path for folding a sheet is disposed on the upper or lower side of the path in the apparatus.
Then, the sheet folding path adopts an apparatus configuration in which, for example, a substantially linear path is disposed in the vertical direction, a sheet carried in the path is folded for first folding, the folded sheet is fed to a substantially linear path disposed on the downstream side to undergo second folding, and the folding-finish sheet is finally fed to a post-processing section on the downstream side.
Thus, conventionally, the sheet folding path provided with the folding processing means is disposed in the apparatus upper portion or lower portion of the transport path for guiding a sheet that does not undergo folding processing to the downstream side, and has a substantially linear path configuration. Therefore, the sheet folding path is configured in a path length corresponding to the length size of the maximum sheet, a second folding path is further formed on the downstream side, and a sheet discharge path is disposed sequentially. Accordingly, the sheet folding path is very long and results in increases in size of the apparatus.
Therefore, the inventor of the invention arrived at the idea of providing the transport path for a sheet that does not undergo folding processing and a sheet folding path to partially cross each other, and is thereby enabling the apparatus to be small and compact.
It is a principal object of the invention to provide a sheet folding apparatus for enabling a sheet folding path for performing folding processing on a sequentially fed sheet to carry to the downstream side to be made small and compact.